All three candidates have flip-flopped on their commitment to that loyalty pledge before, but they most recently said at a Fox News debate in March they'd support the nominee — even if it was Donald Trump.

"Yes, because I gave my word that I would," Cruz said.

"I will support whoever is the Republican nominee for president," Kasich said.

"I'm going to give them some credit, too, even though they don't deserve it, but the answer is yes I will," Trump said.

And there's a possibility of a contested convention in July. So if Trump doesn't get the needed delegates to lock up the nomination, Cruz, Kasich or even someone else from the Republican Party could still be the nominee.